Memory device

ABSTRACT

Systems and methodologies for fabrication of a memory cell or array are disclosed. The memory cell employs a functional zone with passive and active layers. Such passive and active layers facilitate electron migration, and allow a plurality of states for the memory cell. A memory device formed in accordance with the disclosed methodology can include a top-electrode formed over the functional layer, which in turn over lays a lower conductive layer.

CROSS REFERENCE TO RELATED APPLICATION

This application is a Continuation-in-Part of PCT applicationPCT/RU01/00334 filed Aug. 13, 2001.

FIELD OF THE INVENTION

The present invention relates generally to memory devices and, inparticular, to memory cells having functional layer(s) with a mechanismfor electronic switching and resistance change, which is indicative ofdata storage.

BACKGROUND OF THE INVENTION

The volume, use and complexity of computers and electronic devices arecontinually increasing. Computers consistently become more powerful, newand improved electronic devices are continually developed (e.g., digitalaudio players, video players). Additionally, the growth and use ofdigital media (e.g., digital audio, video, images, and the like) havefurther pushed development of these devices. Such growth and developmenthas vastly increased the amount of information desired/required to bestored and maintained for computer and electronic devices.

Generally, information is stored and maintained in one or more of anumber of types of storage devices. Storage devices include long termstorage mediums such as, for example, hard disk drives, compact diskdrives and corresponding media, digital video disk (DVD) drives, and thelike. The long term storage mediums typically store larger amounts ofinformation at a lower cost, but are slower than other types of storagedevices. Storage devices also include memory devices, which are often,but not always, short term storage mediums. Memory devices tend to besubstantially faster than long term storage mediums. Such memory devicesinclude, for example, dynamic random access memory (DRAM), static randomaccess memory (SRAM), double data rate memory (DDR), flash memory, readonly memory (ROM), and the like. Memory devices are subdivided intovolatile and non-volatile types. Volatile memory devices generally losetheir information if they lose power and typically require periodicrefresh cycles to maintain their information. Volatile memory devicesinclude, for example, random access memory (RAM), DRAM, SRAM and thelike. Non-volatile memory devices maintain their information whether ornot power is maintained to the devices. Non-volatile memory devicesinclude, but are not limited to, ROM, programmable read only memory(PROM), erasable programmable read only memory (EPROM), flash memory andthe like. Volatile memory devices generally provide faster operation ata lower cost as compared to non-volatile memory devices.

Memory devices generally include arrays of memory cells. Each memorycell can be accessed or “read”, “written”, and “erased” withinformation. The memory cells maintain information in an “off” or an“on” state (e.g., are limited to 2 states), also referred to as “0” and“1”. Typically, a memory device is addressed to retrieve a specifiednumber of byte(s) (e.g., 8 memory cells per byte). For volatile memorydevices, the memory cells must be periodically “refreshed” in order tomaintain their state. Such memory devices are usually fabricated fromsemiconductor devices that perform these various functions and arecapable of switching and maintaining the two states. The devices areoften fabricated with inorganic solid state technology, such as,crystalline silicon devices. A common semiconductor device employed inmemory devices is the metal oxide semiconductor field effect transistor(MOSFET).

The use of portable computer and electronic devices has greatlyincreased demand for non-volatile memory devices. Digital cameras,digital audio players, personal digital assistants, and the likegenerally seek to employ large capacity non-volatile memory devices(e.g., flash memory, smart media, compact flash, and the like).

Because of the increasing demand for information storage, memory devicedevelopers and manufacturers are constantly attempting to increasestorage capacity for memory devices (e.g., increase storage per die orchip). A postage-stamp-sized piece of silicon may contain tens ofmillions of transistors, each transistor as small as a few hundrednanometers. However, silicon-based devices are approaching theirfundamental physical size limits. Inorganic solid state devices aregenerally encumbered with a complex architecture which leads to highcost and a loss of data storage density. The volatile semiconductormemories based on inorganic semiconductor material must constantly besupplied with electric current with a resulting heating and highelectric power consumption in order to maintain stored information.Non-volatile semiconductor devices have a reduced data rate andrelatively high power consumption and large degree of complexity.Typically, fabrication processes for such cells are also not reliable.

Therefore, there is a need to overcome the aforementioned deficienciesassociated with conventional systems.

SUMMARY OF THE INVENTION

The following presents a simplified summary of the invention in order toprovide a basic understanding of one or more aspects of the invention.This summary is not an extensive overview of the invention. It isintended to neither identify key or critical elements of the invention,nor to delineate the scope of the present invention. Rather, the solepurpose of this summary is to present some concepts of the invention ina simplified form as a prelude to the more detailed description that ispresented hereinafter.

The present invention provided for systems and methods of fabricatingsemiconductor memory devices with a layered functional zone structure.Such functional layer facilitates migration of charges, (e.g. electrons,holes), and allows various impedance states for the memory cell. Thelayered structure can include selective conductive layers),active/passive layers, and barrier layers. Accordingly, a memory cellwith a short resistance switch time and low operating voltages can becreated, which is at the same time compatible with manufacturingmethodologies for existing semiconductors.

According to one aspect of the present invention a top and bottomelectrode sandwich various film layers of functional or selectiveconductive, passive and active layers to form a memory cell. Such memorycell when subjected to an external stimulus, e.g. bias voltages, lightradiation and the like, can be programmed (e.g. write/erase) via adesired impedance state induced in the memory cell. The desiredimpedance state represents one or more bits of information, and does notrequire a constant power supply or refresh cycles to maintain thedesired information. Accordingly, the impedance state of the selectivelyconductive media can be read by applying a further external stimulus,such as an electric current. As with the written impedance state, theread impedance state represents one or more bits of information.Switching between the various states (e.g. read or write) can be afunction of the electrical field created in such memory cell. Ingeneral, such formed electrical field can in turn be a function of thethickness of layers sandwiched between the top and bottom electrodes,and the applied electrical voltage between the first and secondelectrodes.

According to another aspect of the present invention, a multi-cellmemory component can be constructed having two or more non metalelectrodes, e.g. amorphous carbon material, which sandwich therebetweenthe passive and the active layer. In addition, the active layer cancomprise various types of conjugated polymers, such as redox-switchablemolecular units. Under high external electrical field (e.g. 1–10V)electrons or holes can migrate from switchable molecular units to chainsof the conjugated polymers. Such migration of charges can affect aconductivity of the material, and thus change a resistance of the memorycell. The state of the memory cell can then be read by applying a lowexternal electrical voltage, (e.g. 0.05–0.1 V.)

According to one aspect of the present invention, the passive layer canbe deposited upon the lower electrode layer via vacuum thermalevaporation, sputtering, or plasma enhanced chemical vapor deposition(PECVD) utilizing a metal organic (MO) precursor. The deposition processcan be monitored and controlled to facilitate, among other things,depositing the conductivity facilitating compound to a desiredthickness.

To the accomplishment of the foregoing and related ends, the invention,then, comprises the features hereinafter fully described. The followingdescription and the annexed drawings set forth in detail certainillustrative aspects of the invention. However, these aspects areindicative of but a few of the various ways in which the principles ofthe invention may be employed. Other aspects, advantages and novelfeatures of the invention will become apparent from the followingdetailed description of the invention when considered in conjunctionwith the drawings. To facilitate the reading of the drawings, some ofthe drawings may not have been drawn to scale from one figure to anotheror within a given figure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram illustrating a basic organic memory celland its various sub layers in accordance with an aspect of the presentinvention.

FIG. 2 is another schematic diagram of the organic memory cell withvarious active layers and sub layers.

FIG. 3 is a schematic diagram depicting an organic memory device invarious impedance states in accordance with an aspect of the presentinvention.

FIG. 4 is a schematic block diagram illustrating multiple memory layerand memory cell storage and access in accordance with an aspect of thepresent invention.

FIG. 5 is a perspective diagram of a memory device in accordance with anaspect of the present invention.

FIG. 6 is a schematic diagram of a passive layer that can be employed ina memory device in accordance with an aspect of the present invention.

FIG. 7 is a schematic diagram illustrating an organic polymer layer aspart of an active layer formed by a CVD process in accordance with anaspect of the present invention.

FIG. 8 is a schematic diagram illustrating another organic polymer layerformed by a CVD process in accordance with an aspect of the presentinvention.

FIG. 9 is a schematic diagram of yet another organic polymer layerformed by a CVD process in accordance with an aspect of the presentinvention.

FIG. 10 is a graph illustrating I–V characteristics for a memory devicein accordance with an aspect of the present invention.

FIG. 11 is a three dimensional view of a memory device having afunctional layer in accordance with an aspect of the present invention.

FIG. 12 illustrates a flow chart for a methodology according to thepresent invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is now described with reference to the drawings,wherein like reference numerals are used to refer to like elementsthroughout. In the following description, for purposes of explanation,numerous specific details are set forth in order to provide a thoroughunderstanding of the present invention. It may be evident, however, toone skilled in the art that one or more aspects of the present inventionmay be practiced with a lesser degree of these specific details. Inother instances, known structures and devices may be shown in blockdiagram form in order to facilitate describing one or more aspects ofthe present invention.

The invention is based on the problem of creating an essentially newtype of memory cell which is capable of storing several bits ofinformation, which has short resistance switch time and low operatingvoltages and at the same time allow to combine its manufacturingtechnology with that of the modern semiconductors.

This problem is resolved as follows. The memory cell has a three-layerstructure consisting of two electrodes with a functional zone betweenthem. This is achieved by making the electrodes out of metallic and/orsemiconductor and/or conductive polymer and/or optically transparentoxide or sulfide material, making the functional zone out of organic,metalorganic and non-organic materials, with different types of activeelements built into the materials' molecular and/or crystallinestructure, as well as by combining the materials with each other and/orwith clusters based on them that change their; state, electrical chargeand/or position under influence of an external electric field and/orlight radiation.

The described memory cell structure allows creating a memory elementwith single bit and multi-bit information writing, storing and readingmethods. At the same time information is stored as the functional zoneresistance value. For a memory cell with single bit storing mode theresistance value has two levels: high (e.g. representing 0) and low(e.g. representing 1), while for a memory cell with multi-bit storingmode the resistance value has several levels corresponding to specificbits of information. For example, for a two-bit cell there are fourlevels of its resistance, for a four bit cell sixteen levels, and soforth. The memory cell is advantageously distinctive of the currentlyused elements in that it does not require non-interrupted power supplywhile storing information. The information storage time depends on thememory cell structure, on material used for the functional zone, and onrecording mode. The time can vary from several seconds (can be used fordynamic memory) to several years (can be used for long term memory, suchas Flash memory).

The memory cell functional zone may contain an active layer based onorganic and metalorganic conjugate polymers with active elements builtinto the main circuit and/or connected to the circuit or to the planeand/or built into the structure, with the elements forming or notforming a light emitting structure, or of an active layer based onorganic, metalorganic and non-organic materials with instilled positiveor negative ions, including molecular ions, and/or with instilledclusters based on solid electrolytes or with molecules and/or ions withan electric dipole element, and/or with clusters based on solid polymerand non-organic ferroelectrics, and/or with donor and acceptormolecules, and/or with organic and/or non-organic salts and/or acidsand/or alkalis and/or water molecules which can dissociate in anelectric field and/or under light radiation, and/or with non-organicand/or metalorganic and/or organic salts and/or molecules with variablevalency of metals or atomic groups they contain. The describedimplementation of a functional zone allows to create a structure capableof changing the active layer resistance and/or forming high conductivityareas or lines in the active layer under external electric and/or lightradiation effect on the memory cell and retaining this state for a longtime without applying external electric fields.

There are interesting prospects in implementing the functional zone as amultilayer structure containing several layers with various levels ofactivity, implemented, for example, out of organic, metalorganic andnon-organic materials whose molecular and/or crystalline structure haveinstilled active elements based on them, which will change their stateunder electric field or light radiation influence, which allows to widenthe range and quantity of electric resistance levels thereforeincreasing the memory data density.

The functional zone may be implemented as a multilayer structure withalternating active, passive and barrier layers, where the passive layersare being made of organic, metalorganic and non-organic materials whichare donor and/or acceptor charge carriers and possess ion and/orelectron conductivity, while the barrier layer is made of material withhigh electron conductivity and low ion conductivity, which allows toimprove the memory cell stability over time at the same time increasingdata density due to increasing the quantity of the stored values of thememory cell electric resistance.

The memory cell's electrode may be implemented in form of severalseparate elements, for example two or three elements placed above thefunctional layer, which permit more precise control the value of thecell electric resistance, therefore improving the quantity ofinformation recording or the memory cell electric resistance analogvalues precision, as well as allows to decouple the information writingand reading electric circuits.

The memory cell electrode may be implemented in the form of two elementsseparated in a space by a semiconductor and/or organic light emittingmaterial and forming, for example, either a diode structure, or a photoresistance or a photo sensor element, which allows decoupling theinformation writing and reading electric circuits electrically oroptically.

The memory cell electrode may be implemented in the form of threeparallel elements separated in space by a semiconductor and/or organiclight emitting material and forming, for example, a light emittingstructure and a photo resistance or a photo sensor element, which allowsdecoupling the information writing and reading electric circuitsoptically.

FIG. 1 is a cross sectional illustration of a memory cell 100, inaccordance with an aspect of the present invention. The memory cell 100can be formed on a wafer, and typically on a base substrate 102, such assilicon. The cell 100 includes a bottom electrode 104, a functionallayer 103, and a top electrode 110. Unlike conventional inorganic memorycells that can maintain only two states, the memory cell 100 is capableof maintaining two or more states. Thus, a single cell of the memorycell 100 can hold one or more bits of information. Furthermore, thememory cell 100 is a non-volatile memory cell and consequently, does notrequire a constant or nearly constant power supply.

The bottom electrode 104 is formed by depositing a first conductivematerial over the substrate 102. Trenches and/or vias can be formed inthe substrate prior to deposition of such conductive material followedby selectively depositing the first conductive material into thetrenches. According to one aspect of the present invention, theelectrodes 104, 110 can comprise; tungsten, silver, copper, titanium,chromium, germanium, gold, aluminum, magnesium, manganese, indium, iron,nickel, palladium, platinum, zinc, alloys thereof, indium-tin oxide,other conductive oxides, polysilicon, doped amorphous silicon, metalsilicides, and various metal composition alloys. In addition, otherconducting or semi-conducting polymers, PEDOT/PSS, polyaniline,polythiothene material, their derivatives and other doped or undopedconducting and semiconducting organic polymers, oligomers or monomers,conducting and semiconducting metal oxides and nitrides and silicides,conductive organic polymers, and the like, can be employed forfabrication of the electrodes 104 and 110. In addition, since somemetals can have a layer of oxide formed thereupon that can adverselyaffect the performance of the memory cell, non-metal material such asamorphous carbon can also be employed for electrode formation. Inaddition, other conductive polymers and/or optically transparent oxideor sulfide material can be employed in forming the electrodes 104, and110.

As illustrated in FIG. 1, sandwiched between the two electrodes 104,110, is a functional zone 103. Such functional zone can itself compriseof organic, metal organic, and non-organic materials, in the form of anactive layer 108 and a passive layer 106.

The passive layer 106 is operative to transport charge from theelectrode 104 to the interface between the active layer 108 and thepassive layer 106. Additionally, the passive layer 106 facilitatescharge carrier (e.g., electrons or holes) and/or metal ion injectioninto the active layer 108 and increases the concentration of the chargecarrier and/or metal ions in the active layer 108 resulting in amodification of the conductivity of the active layer 108. Furthermore,the passive layer 106 can also store opposite charges in the passivelayer 106 in order to balance the total charge of the device 100. Boththe passive layer 106 and the active layer 108 can comprise further sublayers, as shown in FIG. 1.

As further illustrated in FIG. 1, the passive layer 106 can be part ofthe functional layer 103, which is formed on the bottom electrode 104.The passive layer 106 contains at least one conductivity facilitatingcompound that has the ability to donate and accept charges (holes and/orelectrons). Generally, the conductivity facilitating compound has atleast two relatively stable oxidation-reduction states that can permitthe conductivity facilitating compound to donate and accept charges.Passive layer 106 should also be capable of donating and accepting ions.Examples of other conductivity facilitating compounds that can beemployed for the passive layer 106 include one or more of the following:tungsten oxide (WO₃), molybdenum oxide (MoO₃), titanium dioxide (TiO₂),and the like.

The passive layer 106 can in some instances act as a catalyst whenforming the active layer 108. In this connection, a backbone of aconjugated organic molecule can initially form adjacent the passivelayer 106, and grow or assemble away and substantially perpendicular tothe passive layer surface. As a result, the backbones of the conjugatedorganic molecule can be self aligned in a direction that traverses thetwo electrodes. The passive layer can be formed by a deposition process(e.g. thermal deposition, PVD, non-selective CVD, and the like) or by acomplete sulfidation of pre-deposited thin Cu layer.

Referring now to the active layer 108, such layer can include variousorganic, metal organic conjugate polymers. In addition, various lightemitting material, such as; light emitting structure, photo resistance,or photo sensors can be part of the active layer 108. Moreover,additional material with donor/acceptor charges such as; moleculesand/or ions with an electric dipole element, polymer ferroelectricsclusters, non-organic ferro-electrics, salts, alkalis and acids (organicor non organic), water molecules, materials with molecules that candissociate in an electrical field and/or under radiation, organic saltsand/or molecules with variable valency of metals, can also be employedas part of the active layer 108. As such, examples of organic,non-organic salts, alkalis, acids and molecules that can dissociate inan electric field and/or under light radiation can include the followinganions: I, Br, Cl, F, ClO₄, AlCl₄, PF₆, AsF₆, AsF₄, SO₃CF₃, BF₄, BCl₄,NO₃, POF₄, CN, SiF₃, SiF₆, SO₄, CH₃CO₂, C₆H₅CO₂, CH₃C₆H₄SO₃, CF₃SO₃,N(SO₃CF₃)₂, N(CF₃SO₂)(C₄F₉SO₂), N(C₄F₉SO₂)₂, alkylphosphate,organoborate, bis-(4-nitrophenil) sulfonilimide, poly(styrenesulfonate)(polyanions)— and for cations such as: Li, Na, K, Rb, Cs, Ag,Ca, Mg, Zn, Fe, Cu, H, NH₄ and the like. Similarly, examples of clustersemployed in the active layer 108 that are based on polymer ferroelectrics and non-organic ferro-electrics can include poly(vinylidenefluoride), poly(vinylidene fluoride)/trifluoroethylene, and the like.

In a related aspect of the present invention, various porous dielectricmaterials can also be employed as part of the functional layer 103. Suchporous material for example, can include matter selected from the groupof Si, amorphous Si, silicon dioxide (SiO₂), aluminum oxide (Al₂O₃),copper oxide (Cu₂O), titanium dioxide (TiO₂), boron nitride (BN),vanadium oxide (V₂O₃), carbon tri-nitride (CN₃), and ferroelectricmaterials, including barium-strontium titanate ((Ba, Sr) TiO₃).

In accordance with another aspect of the present invention, the activelayer 108 of the memory cell 100 can include polymers with variableelectric conductivity. Such polymers with variable electricalconductivity can include; polydiphenylacetylene,poly(t-butyl)diphenylacetylene, poly(trifluoromethyl)diphenylacetylene,polybis-trifluoromethyl)acetylene, polybis(t-butyldiphenyl)acetylene,poly(trimethylsilyl) diphenylacetylene,poly(carbazole)diphenylacetylene, polydiacetylene, polyphenylacetylene,polypyridineacetylene, polymethoxyphenylacetylene,polymethylphenylacetylene, poly(t-butyl)phenylacetylene,polynitro-phenylacetylene, poly(trifluoromethyl)phenylacetylene,poly(trimethylsilyl)pheylacetylene, polydipyrrylmethane,polyindoqiunone, polydihydroxyindole, polytrihydroxyindole,furane-polydihydroxyindole, polyindoqiunone-2-carboxyl, polyindoqiunonemonohydrate, polybenzobisthiazole, poly(p-phenylene sulfide) andderivatives with active molecular group.

As used in this application, an active molecule or molecular group canbe one that changes a property when subjected to an electrical field orlight radiation, (e.g. iozinable group); such as: nitro group, aminogroup, cyclopentadienyl, dithiolane, metilcyclopentadienyl,fulvalenediyl, indenyl, fluorenyl, cyclobis(paraquart-p-phenylene),bipyridinium, phenothiazine, diazapyrenium, benzonitrile, benzonate,benzamide, carbazole, dibenzothiophene, nitrobenzene,aminobenzenesulfonate, amonobenzanate, and molecular units withredox-active metals; metallocenes (Fe, V, Cr, Co, Ni and the like)complex, polypyridine metal complex (Ru, Os and the like).

In another aspect of the present invention, the active layer 108 caninclude polymers such as polyaniline, polythiophene, polypyrrole,polysilane, polystyrene, polyfuran, polyindole, polyazulene,polyphenylene, polypyridine, polybipyridine, polyphthalocyanine,polysexithiofene, poly(siliconoxohemiporphyrazine),poly(germaniumoxohemiporphyrazine), poly(ethylenedioxythiophene) andrelated derivatives with active molecular group. It is to be appreciatedthat other suitable and related chemical compounds can also be employedincluding: aromatic hydrocarbons; organic molecules with donor andacceptor properties (N-Ethylcarbazole, tetrathiotetracene,tetrathiofulvalene, tetracyanoquinodimethane, tetracyanoethylene,cloranol, dinitro-n phenyl and so on); metallo-organic complexes(bisdiphenylglyoxime, bisorthophenylenediimine,tetraaza-tetramethylannulene and so on); porphyrin, phthalocyanine,hexadecafluoro phthalocyanine and their derivatives with activemolecular group.

In general, the memory cell structure 100 employing the materialdiscussed supra can exhibit a formation of high conductivity areas, oraffect a resistance of the functional zone 103 in response to anexternal stimulus such as an electric voltage, electric current, lightradiation, and the like. For example, presence of ferro-electricmaterial can increase an internal electric field intensity, and as aresult application of a lower external electric voltage can be requiredfor a writing of the memory cell 100. As explained supra, the activelayer 108 can be created on the passive layer 106 and results in aninterface between the two layers. Moreover, the active layer 108 can beformed via a number of suitable techniques. One such technique involvesgrowing the active layer 108 in the form of an organic layer from thepassive layer 106. Another technique that can be utilized is a spin-ontechnique which involves depositing a mixture of the material and asolvent, and then removing the solvent from the substrate/electrode.Another suitable technique is chemical vapor deposition (CVD). CVDincludes low pressure chemical vapor deposition (LPCVD), plasma enhancedchemical vapor deposition (PECVD), and high density chemical vapordeposition (HDCVD). It is not typically necessary to functionalize oneor more ends of the organic molecule in order to attach it to anelectrode/passive layer. Sometime it may have a chemical bond formedbetween the conjugated organic polymer of the active layer 108 and thepassive layer 106.

In one aspect of the present invention, the active layer 108 can also becomprised of a conjugated organic material, such as a small organicmolecule and a conjugated polymer. If the organic layer is polymer, apolymer backbone of the conjugated organic polymer may extend lengthwisebetween the electrodes 104 and 110 (e.g., generally substantiallyperpendicular to the inner, facing surfaces of the electrodes 104 and110). The conjugated organic molecule can be linear or branched suchthat the backbone retains its conjugated nature. Such conjugatedmolecules are characterized in that they have overlapping π orbitals andthat they can assume two or more resonant structures. The conjugatednature of the conjugated organic materials contributes to thecontrollably conductive properties of the selectively conductive media.

In this connection, the conjugated organic material of the active layer108 has the ability to donate and accept charges (holes and/orelectrons). Generally, the conjugated organic molecule has at least tworelatively stable oxidation-reduction states. The two relatively stablestates permit the conjugated organic polymer to donate and acceptcharges and electrically interact with the conductivity facilitatingcompound.

The organic material employed as part of the active layer 108 accordingto one aspect of the present invention can be cyclic or acyclic. Forsome cases, such as organic polymers, the organic material can selfassemble on bottom electrode during formation or deposition. Examples ofconjugated organic polymers include one or more of polyacetylene (cis ortrans); polyphenylacetylene (cis or trans); polydiphenylacetylene;polyaniline; poly(p-phenylene vinylene); polythiophene; polyporphyrins;porphyrinic macrocycles, thiol derivatized polyporphyrins;poly(p-phenylene)s; poly(imide)s; polymetallocenes such aspolyferrocenes, polyphthalocyanines; polyvinylenes; polystiroles; andthe like. Additionally, the properties of the organic material can bemodified by doping with a suitable dopant.

The top electrode 110 is formed on/over the organic material of theactive layer 108 and/or the passive layer 106. The top electrode 110 canbe comprised of similar material as described supra for the lowerelectrode 104. Additionally, alloys with phosphorous, nitrogen, carbon,and boron, graphite, conductive oxides and other conductive substancescan also be employed.

The thickness of the bottom electrode 104 and the top electrode 110 canvary depending on the implementation and the memory cell beingconstructed. However, some exemplary thickness ranges include about 0.01μm or more and about 10 μm or less, about 0.05 μm or more and about 5 μmor less, and/or about 0.1 μm or more and about 1 μm or less.

The active layer 108 and the passive layer 106 can be collectivelyreferred to as a selectively conductive media or a selectivelyconductive layer, which is a part of the functional zone 103. Theconductive properties of this media (e.g., conductive, non-conductive,semi-conductive) can be modified in a controlled manner by applyingvarious voltages across the media via the electrodes 104 and 110.

The organic layer that in one exemplary aspect can form the active layer108, has a suitable thickness that depends upon the chosenimplementations and/or the memory cell being fabricated. Some suitableexemplary ranges of thickness for the organic polymer layer, which inpart can form the active layer 108, are about 0.001 μm or more and about5 μm or less, about 0.01 μm or more and about 2.5 μm or less, and abouta thickness of about 0.05 μm or more and about 1 μm or less. Similarly,the passive layer 106 has a suitable thickness that can vary based onthe implementation and/or memory cell being fabricated. Some examples ofsuitable thicknesses for the passive layer 106 are as follows: athickness of about 2 Å or more and about 0.1 μm or less, a thickness ofabout 10 Å or more and about 0.01 μm or less, and a thickness of about50 Å or more and about 0.005 μm or less.

In order to facilitate operation of the memory cell 100, the activelayer 108 is generally thicker than the passive layer 106. In oneaspect, the thickness of the active layer is from about 0.1 to about 500times greater than the thickness of the passive layer. It is appreciatedthat other suitable ratios can be employed in accordance with thepresent invention. It is to be appreciated that the various layersemployed in fabricating the memory cell can themselves comprise aplurality of sub layers, as depicted in FIG. 1 wherein passive layer106, and active layer 108, are each shown as comprising threesub-layers.

The memory cell 100, like conventional memory cells, can have twostates, a conductive (low impedance or “on”) state or non-conductive(high impedance or “off”) state. However, unlike conventional memorycells, the memory cell 100 is able to have/maintain a plurality ofstates, in contrast to a conventional memory cell that is limited to twostates (e.g., off or on). The memory cell can employ varying degrees ofconductivity to identify additional states. For example, the memory cell100 can have a low impedance state, such as a very highly conductivestate (very low impedance state), a highly conductive state (lowimpedance state), a conductive state (medium level impedance state), anda non-conductive state (high impedance state) thereby enabling thestorage of multiple bits of information in a single organic memory cell,such as 2 or more bits of information or 4 or more bits of information(e.g., 4 states providing 2 bits of information, 8 states providing 3bits of information, and the like.)

Switching the memory cell 100 to a particular state is referred to asprogramming or writing. Programming is accomplished by applying aparticular voltage (e.g., 9 volts, 2 volts, 1 volt, . . . ) across theselectively conductive media via the electrodes 104 and 110. Theparticular voltage, also referred to as a threshold voltage, variesaccording to a respective desired state and is generally substantiallygreater than voltages employed during normal operation. Thus, there istypically a separate threshold voltage that corresponds to respectivedesired states (e.g., “off”, “on” . . . ). The threshold value variesdepending upon a number of factors including the identity of thematerials that constitute the memory cell 100, the thickness of thevarious layers, and the like. Generally speaking, the presence of anexternal stimuli such as an applied electric field that exceeds athreshold value (“on” state) permits an applied voltage to write, read,or erase information into/from the memory cell 100; whereas the absenceof the external stimuli that exceeds a threshold value (“off” state)prevents an applied voltage to write or erase information into/from thememory cell 100.

To read information from the memory device, a voltage or electric field(e.g., 2 volts, 1 volt, 0.5 volts) is applied via a voltage source.Then, an impedance measurement is performed which, therein determineswhich operating state the memory device is in (e.g., high impedance,very low impedance, low impedance, medium impedance, and the like). Asstated supra, the impedance relates to, for example, “on” (e.g., 1) or“off” (e.g., 0) for a dual state device or to “00”, “01”, “10”, or “11”for a quad state device. It is appreciated that other numbers of statescan provide other binary interpretations. To erase information writteninto the organic memory device, a negative voltage or a polarityopposite the polarity of the writing signal that exceeds a thresholdvalue is applied.

FIG. 2 illustrates another exemplary structure for a memory cell 200 inaccordance with the present invention. A first or lower conductive layeris deposited on an upper surface of an insulating layer. The lowerconductive layer can comprise aluminum, titanium, tungsten, platinum,palladium and their alloys and nitrides, conductive oxides and amorphouscarbon (a-C). Such first or lower conductor layer can be about 1000Å–5000 Å thick. Upon this lower conductive and active layer isdeposited. Such active layer can comprise; polymerpolyphenilacetylene+molecules of chloranil or tetracyano-quino-dimethaneor dichlordicyanoquinone, (which can be deposited from solution byspin-coating); copper phthalocyanine (which can be deposited by thermaldeposition method to about 30 Å–1000 Å); copper hexadecafluorophthalocyanine, amorphous carbon or palladium, (which can be depositedon the upper surface of the active layer by magnetron co-sputtering);porous silicon oxide (SiO₂) and polisilanes with N-carbazolylpropylgroup; polymer polytiophene with cyclopentadienyl groups, (which can bedeposited from solution by spin-coating; polisilanes withN-carbazolylpropyl group); polisilanes with cyclopentadienyl groups;polisilanes with amino groups; polytiophene with alkyl amino groups;polytiophene with cyclopentadienyl alkyl groups; composite containingpolydiphenilacetylene containing carbazolyl groups and dinitro-n-phenyl(DNP); polyethylenedioxythiophene and Li CF₃SO₃ salt containing porousferroelectric (polyvinyline fluoride), polydiphenilacetylene containingcarbazolyl groups dinitro-n-phenyl (DNP); polyethylenedioxythiophene andsalt of potassium hexycyanoferrate.

FIG. 3 is a schematic diagram that illustrates an organic memory device300 in various states in accordance with an aspect of the presentinvention. The device 300 is depicted in a first “off” state 301, an“on” state 302, and a second “off” state 303. It is appreciated thatmemory devices formed in accordance with the present invention can haveother states than those depicted in FIG. 3. The organic memory device300 comprises a top electrode 304, a bottom electrode 306 and aselectively conductive layer 308 and at least one passive layer. Inaddition, various barrier layers, for example comprised of material suchas Li₃N, can be placed at various locations among the active layer,passive layer and electrodes. In the first off state 301, electrons 310collect in the selectively conductive layer 308 near the bottomelectrode 306. In the on state 302, the electrons 310 are uniformlydistributed thereby indicating an on state. In the second off state 303,the electrons collect in the selectively conductive layer 308 near thetop electrode 304.

Turning to FIG. 4, an array 400 of memory cells in accordance with anaspect of the present invention is illustrated. Such an array isgenerally formed on a silicon based wafer, and includes a plurality ofcolumns 402, referred to as bitlines, and a plurality of rows 404,referred to as wordlines. Such bit line and wordlines can be connectedto the top and bottom metal layers of the memory component. Theintersection of a bitline and a wordline constitutes the address of aparticular memory cell. Data can be stored in the memory cells (e.g., asa 0 or a 1) by choosing and sending signals to appropriate columns androws in the array (e.g., via a column address strobe (CAS) 406 and a rowaddress strobe (RAS) 408, respectively). For example, the state (e.g., a0 or a 1) of the memory cell indicated at 410 is a function of the3^(rd) row and 8^(th) column of the array 400. In dynamic random accessmemory (DRAM), for example, memory cells include transistor-capacitorpairs. To write to a memory cell, a charge can be sent to theappropriate column (e.g., via CAS 406) to activate the respectivetransistors in the columns, and the state that respective capacitorsshould take on can be sent to the appropriate columns (e.g., via RAS408). To read the state of the cells, a sense-amplifier can determinethe level of charge on the capacitors. If it is more than 50 percent, itcan be read as a 1; otherwise it can be read as a 0. It is to beappreciated that while the array 400 illustrated in FIG. 4 includes 64memory cells (e.g., 8 rows×8 columns), the present invention hasapplication to any number of memory cells and is not to be limited toany particular configuration, arrangement and/or number of memory cells.

Now referring to FIG. 5, a perspective diagram of an organic memorydevice in accordance with an aspect of the present invention isdepicted. The memory device includes a first electrode 504, a passivelayer 506, an organic polymer layer 508, and a second electrode 510. Thediagram also illustrates a voltage source 502 connected to the firstelectrode 504 and the second electrode 510 that can apply an externalstimulus in form of a voltage on the first electrode 504 and the secondelectrode 510.

The first electrode 504 and the second electrode 510 are comprised of aconductive material, such as, aluminum, chromium, germanium, carbon,hafnium, indium, rhenium, ruthenium, tungsten, gold, magnesium,manganese, indium, iron, nickel, palladium, platinum, silver, titanium,zinc, alloys thereof, indium-tin oxide, polysilicon, doped amorphoussilicon, metal carbides, nitrides and silicides, conducting oxides,semiconducting oxides, polysilicon, doped amorphous silicon, metalsilicides, metal nitrides and silicides and the like. Exemplary alloysthat can be utilized for the conductive material include Hastelloy®,Kovar®, Invar, Monel®, Inconel®, stainless steel, magnesium-silveralloy, and various other alloys.

As explained supra, the presence of an external stimuli; such as anapplied electric field that exceeds a threshold value (“on” state),permits an applied voltage 502 to write, read, or erase informationinto/from the organic memory cell; whereas the absence of the externalstimuli that exceeds a threshold value (“off” state) prevents an appliedvoltage to write or erase information into/from the organic memory cell.

FIG. 6 is a schematic diagram that depicts a passive layer 600 inaccordance with an aspect of the present invention. A first layer 606 isformed that forms the lower electrode. A second layer 604 is formed onthe first layer. The second layer comprises Cu_(x)S and has a thicknessof about 20 Å or more. A third layer 602 is formed on the second layer604. The third layer 602 contains Cu₂O, and/or CuO and generally has athickness of about 10 Å or less. It is appreciated that alternateaspects of the invention can employ suitable variations in compositionand thickness and still be in accordance with the present invention.

FIG. 7 is a schematic diagram illustrating an organic layer 700 formedby a chemical vapor deposition (CVD) process as part of the active layerin accordance with an aspect of the present invention. The organic layer700 is formed via a gas phase reaction process. Typically, the organiclayer 700 is formed in contact with a passive layer and an electrode.The organic layer 700 is comprised of polymer polydiphenylacetylene(pDPA). This polymer layer, as shown can be fabricated to be about 750 Åthick.

Turning now to FIG. 8, a diagram depicting another organic layer 800formed from a CVD process in accordance with an aspect of the presentinvention is illustrated. Once again, the organic layer 800 is formedvia a gas phase reaction process. The organic layer 800 is formed incontact with a passive layer and an electrode. The organic polymer layer800 is comprised of polymer polyphenylacetylene (PPA).

Referring to FIG. 9, a block diagram of another organic layer 900 aspart of the active layer of a memory cell formed by spin coating inaccordance with an aspect of the present invention is illustrated. Theorganic layer 900 is formed via a spin coating process, instead of a gasphase reaction process. The organic layer 900 is formed in contact witha passive layer and an electrode. The organic layer 900 is comprisedsubstantially of PPA and has a thickness of about 1000 Å.

Experimental results tend to show that organic layers formed via spincoating yield a more reliable polymer layer than polymer layers formedvia CVD. This may be due to the presence of oxygen and lack of controlof heat generated by polymerization under CVD. It is appreciated thatcontrolling heat and oxygen during polymerization for CVD processes canimprove the resulting polymer layer.

It is appreciated that various alternatives to and variations of thelayers described in FIGS. 6–9 can be employed in accordance with thepresent invention. Moreover, it is to be appreciated that other methodsof forming the active layer can be employed such as liquid phasereaction process, e.g. self assembling of an active layer(s) on bottomelectrode (or a passive layer) via application of a suitable chemicalcompound.

FIG. 10 is a graph 1000 that illustrates an I–V graph for a memorydevice in accordance with an aspect of the present invention. It can beseen that from state 1, which indicates “off”, the device can bemodified to be in state 2, which indicates “on”, by applying a positivevoltage. Additionally, it can be seen that whilst in state 1, theorganic memory device has a high impedance and low conductance.Subsequently, the device can be modified to change from state 2 to state1 by application of a negative voltage, therein causing a reversecurrent until the state 1 is obtained.

Referring to FIG. 11, a three dimensional view of a memory device 1100containing a plurality of memory cells with functional zones inaccordance with an aspect of the invention is shown. The memory device1100 contains a plurality of first electrodes 1102, a plurality ofsecond electrodes 1104, and a plurality of memory cell layers 1106.Between the respective first and second electrodes are the controllablyconductive media (not shown). The plurality of first electrodes 1102 andthe plurality of second electrodes 1104 are shown in substantiallyperpendicular orientation, although other orientations are possible. Thethree dimensional microelectronic memory device is capable of containingan extremely high number of memory cells thereby improving devicedensity. Peripheral circuitry and devices are not shown for brevity.

The memory cells/devices are useful in any device requiring memory. Forexample, the memory devices are useful in computers, appliances,industrial equipment, hand-held devices, telecommunications equipment,medical equipment, research and development equipment, transportationvehicles, radar/satellite devices, and the like. Hand-held devices, andparticularly hand-held electronic devices, achieve improvements inportability due to the small size and light weight of the memorydevices. Examples of hand-held devices include cell phones and other twoway communication devices, personal data assistants, palm pilots,pagers, notebook computers, remote controls, recorders (video andaudio), radios, small televisions and web viewers, cameras, and thelike.

FIG. 12 illustrates a methodology according to one aspect of the presentinvention.

While the exemplary method is illustrated and described herein as aseries of blocks representative of various events and/or acts, thepresent invention is not limited by the illustrated ordering of suchblocks. For instance, some acts or events may occur in different ordersand/or concurrently with other acts or events, apart from the orderingillustrated herein, in accordance with the invention. In addition, notall illustrated blocks, events or acts, may be required to implement amethodology in accordance with the present invention. Moreover, it willbe appreciated that the exemplary method and other methods according tothe invention may be implemented in association with a deposition andetch process for IC fabrication, and/or a damascene fill and polishprocedure as well as in association with other systems and apparatus notillustrated or described.

Initially, at 1202 a bottom metal layer is being deposited, e.g., aspart of an interconnect line as described in detail supra. Next at 1204a passive layer, as discussed in detail supra, is formed over the bottommetal layer. At 1206, and over the passive layer, an active layer isbeing deposited. Next and at 1208, a top metal layer is being formedover the active layer, e.g., as part of an interconnect line. Inaddition, layers of the memory component can be associated with and/orpart of a memory cell or array, as described in more detail supra.

The following examples illustrate various particular aspects of thepresent invention. Unless otherwise indicated in the following examplesand elsewhere in the specification and claims, all parts and percentagesare by weight, all temperatures are in degrees Centigrade, and pressureis at or near atmospheric pressure.

EXAMPLE 1

Ti/polyphenylacetylene+molecules of chloraniline ortetracyano-quino-dimethane/amorphous carbon (a-C). A first or lowerconductive conductor is deposited on an upper surface of an insulatinglayer. The first or lower conductor may be formed from materialsselected from: aluminum, titanium, tungsten, platinum, palladium andtheir alloys and nitrides, conductive oxides and amorphous carbon (a-C).The first or lower conductor layer is about 3000 Å thick. The activelayer is mixture of a polymer polyphenylacetylene+molecules ofchloraniline or tetracyano-quino-dimethane or dichlordicyanoquinone,which may be deposited from solution by spin-coating. The active layeris about 500 Å thick. The second conductor layer is amorphous carbon orpalladium, which can be deposited on the upper surface of the activelayer by magnetron co-sputtering. The second conductor layer is about2000 Å thick.

EXAMPLE 2

Ti/copper phthalocyanine/cupper hexadecafluoro phthalocyanine/a-C or Pdor ITO. A first or lower conductive conductor is deposited on an uppersurface of an insulating layer. The first or lower conductor may beformed from titanium and is about 3000 Å thick. The lower active layeris copper phthalocyanine which can be deposited by thermal depositionmethod and is about 50 Å thick. The upper active layer is copperhexadecafluoro phthalocyanine which can be deposited by thermaldeposition method and is about 50 Å thick. The second conductor layer isamorphous carbon, which can be deposited on the upper surface of thesecond polyaniline active layer by magnetron co-sputtering. The secondconductor layer is about 2000 Å thick.

EXAMPLE 3

Ti/polysilanes with N-carbazolylpropyl group+silicon oxide (SiO₂)/a-C orPd or ITO. This cell is fabricated in a similar manner as Example 1,except that the active layer is a composite of containing porous siliconoxide (SiO₂) and polysilanes with N-carbazolylpropyl group.

EXAMPLE 4

Ti/Polythiophene with cyclopentadienyl groups/amorphous carbon (a-C). Afirst or lower conductive conductor is deposited on an upper surface ofan insulating layer. The first or lower conductor may be formed frommaterials selected from: aluminum, titanium, tungsten, platinum,palladium and their alloys and nitrides, conductive oxides, andamorphous carbon (a-C). The first or lower conductor layer is about 3000Å thick. The active layer is mixture of a polymer polythiophene withcyclopentadienyl groups, which may be deposited from solution byspin-coating. The active layer is about 500 Å thick. The secondconductor layer is amorphous carbon or palladium, which can be depositedon the upper surface of the active layer by magnetron co-sputtering. Thesecond conductor layer is about 2000 Å thick.

EXAMPLE 5

Ti/polysilanes with N-carbazolylpropyl group/a-C or Pd or ITO. This cellis fabricated in a similar manner as Example 4, except that the activelayer is polysilanes with N-carbazolylpropyl group.

EXAMPLE 6

Pd/polysilanes containing cyclopentadienyl groups/a-C or Pd or ITO. Thiscell is fabricated in a similar manner as Example 4, except that theactive layer is polysilanes with cyclopentadienyl groups.

EXAMPLE 7

Pd/polysilanes with amino groups/a-C or Pd or ITO. This cell isfabricated in a similar manner as Example 4, except that the activelayer is polysilanes with amino groups.

EXAMPLE 8

Ti/Polythiophene with amino groups/a-C or Pd or ITO. This cell isfabricated in a similar manner as Example 4, except that the activelayer is polythiophene with amino groups.

EXAMPLE 9

Ti/Polythiophene with alkyl amino groups/a-C or Pd or ITO. This cell isfabricated in a similar manner as Example 4, except that the activelayer is polythiophene with alkyl amino groups.

EXAMPLE 10

Ti/Polythiophene with cyclopentadienyl alkyl groups/a-C or Pd or ITO.This cell is fabricated in a similar manner as Example 4, except thatthe active layer is polythiophene with cyclopentadienyl alkyl groups.

EXAMPLE 11

Ti/Polythiophene with cyclopentadienyl groups/a-C or Pd or ITO. Thiscell is fabricated in a similar manner as Example 4, except that theactive layer is polythiophene with cyclopentadienyl alkyl groups.

EXAMPLE 12

Ti/Polydiphenilacetylene with carbazolyl groups+dinitro-n-phenyl(DNP)/a-C. This cell was fabricated in a similar manner as Example 4,except that the active layer is a composite containingpolydiphenilacetylene containing carbazolyl groups anddinitro-n-phenyl(DNP).

EXAMPLE 13

Ti/polyethylenedioxythiophene+Li CF₃SO₃/Pd. This cell is fabricated in asimilar manner as Example 4, except that the active layer is a compositeof containing polyethylenedioxythiophene and LiCF₃SO₃ salt.

EXAMPLE 14

Ti/polydiphenylacetylene containing carbazolyl groups+dinitro-n-phenyl(DNP)+porous ferroelectric (polyvinyline fluoride)/a-C. This cell isfabricated in a similar manner as Example 4, except that the activelayer is a composite of containing porous ferroelectric (polyvinylinefluoride), polydiphenylacetylene containing carbazolyl groups anddinitro-n-phenyl(DNP).

EXAMPLE 15

Ti/polyethylenedioxythiophene+salt of potassium hexycyanoferrate/Pd.This cell is fabricated in a similar manner as Example 4, except thatthe active layer is a composite of containing polyethylenedioxythiopheneand salt of potassium hexycyanoferrate.

Although the invention has been shown and described with respect tocertain illustrated aspects, it will be appreciated that equivalentalterations and modifications will occur to others skilled in the artupon the reading and understanding of this specification and the annexeddrawings. In particular regard to the various functions performed by theabove described components (assemblies, devices, circuits, systems,etc.), the terms (including a reference to a “means”) used to describesuch components are intended to correspond, unless otherwise indicated,to any component which performs the specified function of the describedcomponent (e.g., that is functionally equivalent), even though notstructurally equivalent to the disclosed structure, which performs thefunction in the herein illustrated exemplary aspects of the invention.In this regard, it will also be recognized that the invention includes asystem as well as a computer-readable medium having computer-executableinstructions for performing the acts and/or events of the variousmethods of the invention.

In addition, while a particular feature of the invention may have beendisclosed with respect to only one of several implementations, suchfeature may be combined with one or more other features of the otherimplementations as may be desired and advantageous for any given orparticular application. Furthermore, to the extent that the terms“includes”, “including”, “has”, “having”, and variants thereof are usedin either the detailed description or the claims, these terms areintended to be inclusive in a manner similar to the term “comprising”.

1. A memory device comprising: a first electrode; a functional mediaformed over the first electrode, the functional media stores informationbased on a change of an impedance state, the impedance state of thefunctional media chances based on a migration of electrons or holes whensubject to an external electric field or light radiation, the impedancestate indicative of information content, the functional mediacomprising 1) an active layer having an ability to donate and acceptcharges and 2) a passive layer comprising a conductivity facilitatingcompound having at least two stable oxidation-reduction states and anability to donate and accept charges, the active layer having athickness that is about 0.1 to about 500 times greater than a thicknessof the passive layer; and a second electrode formed over the functionalmedia.
 2. The memory device of claim 1, wherein the active layercomprises organic material selected from the group comprising ofpolyacetylene, polyphenylacetylene, and polydiphenylacetylene.
 3. Thememory device of claim 1, wherein the first electrode or the secondelectrode comprises at least one selected from the group of tungsten,silver, copper, titanium, chromium, germanium, gold, aluminum,magnesium, manganese, indium, iron, nickel, palladium, platinum, zinc,alloys thereof, indium-tin oxide, conductive oxides, polysilicon, dopedamorphous silicon, metal silicides, and various copper compositionalloys.
 4. The memory device of claim 1, wherein the first electrode orthe second electrode comprise at least one selected from the group ofconducting polymers, semi-conducting polymers, PEDOT/PSS, polyaniline,polythiothene material, doped conducting organic polymers, dopedsemiconducting organic polymers, undoped conducting organic polymers,undoped semiconducting organic polymers, oligomers, monomers, conductingmetal oxides, conducting metal nitrides, conducting metal silicides,semiconducting metal oxides, semiconducting metal nitrides,semiconducting metal silicides, and conductive organic polymers.
 5. Thememory device of claim 1, wherein the first electrode or the secondelectrode comprise amorphous carbon.
 6. The memory device of claim 1,wherein the first electrode or the second electrode comprise at leastone of optically transparent oxide and sulfide material.
 7. The memorydevice of claim 1, wherein the active layer comprises at least one of anorganic, metal organic, and non organic material.
 8. The memory deviceof claim 1, wherein the active layer comprises at least one selectedfrom the group of polydiphenylacetylene, poly(t-butyl)diphenylacetylene,poly(trifluoromethyl)diphenylacetylene,polybis-trifluoromethyl)acetylene, polybis(t-butyldiphenyl)acetylene,poly(trimethylsilyl) diphenylacetylene,poly(carbazole)diphenylacetylene, polydiacetylene, polyphenylacetylene,polypyridineacetylene, polymethoxyphenylacetylene,polymethylphenylacetylene, poly(t-butyl)phenylacetylene,polynitro-phenylacetylene, poly(trifluoromethyl) phenylacetylene,poly(trimethylsilyl)pheylacetylene, polydipyrrylmethane,polyindoqiunone, polydihydroxyindole, polytrihydroxyindole,furane-polydihydroxyindole, polyindoqiunone-2-carboxyl, polyindoqiunonemonohydrate, polybenzobisthiazole, and poly(p-phenylene sulfide).
 9. Thememory device of claim 1, wherein the active layer comprises at leastone of: materials of a nitro group, materials of an amino group,cyclopentadienyl, dithiolane, metilcyclopentadienyl, fulvalenediyl,indenyl, fluorenyl, cyclobis(paraquart-p-phenylene), bipyridinium,phenothiazine, diazapyrenium, benzonitrile, benzonate, benzamide,carbazole, dibenzothiophene, nitrobenzene, aminobenzenesulfonate, andamonobenzanate.
 10. The memory device of claim 1, wherein the activelayer comprises molecular units with redox-active metals.
 11. The memorydevice of claim 10, wherein the redox active metals comprise at leastone of metallocenes complex and polypyridine metal complex.
 12. Thememory device of claim 1, wherein the active layer comprises at leastone selected from the group of polyaniline, polythiophene, polypyrrole,polysilane, polystyrene, polyfuran, polyindole, polyazulene,polyphenylene, polypyridine, polybipyridine, polyphthalocyanine,polysexithiofene, poly(siliconoxohemiporphyrazine),poly(germaniumoxohemiporphyrazine), and poly(ethylenedioxythiophene).13. The memory device of claim 1, wherein active layer comprises atleast one selected from the group of aromatic hydrocarbons; organicmolecules with donor and acceptor properties, metallo-organic complexes;porphyrin, phthalocyanine, and hexadecafluoro phthalocyanine.
 14. Thememory device of claim 13, wherein the organic molecules with donoracceptor properties comprises at least one selected from the group ofN-Ethylcarbazole, tetrathiotetracene, tetrathiofulvalene,tetracyanoquinodimethane, tetracyanoethylene, cloranol, and dinitro-nphenyl.
 15. The memory device of claim 13, wherein the metallo-organiccomplexes are selected from the group of bisdiphenylglyoxime,bisorthophenylenediimine, and tetraaza-tetramethylannulene.
 16. Thememory device of claim 1, wherein the active layer comprises organicmaterial selected from the group comprising of polyacetylene,polyphenylacetylene, polydiphenylacetylene, polyaniline,poly(p-phenylene vinylene), polythiophene, polyporphyrins, porphyrinicmacrocycles, thiol derivatized polyporphyrins, polymetallocenes,polyferrocenes, polyphthalocyanines, polyvinylenes, and polystiroles.17. The memory device of claim 1, wherein the active layer comprisesmaterial selected from the group comprising of electric dipole elements,polymer ferroelectrics clusters, non-organic ferro-electrics, salts,alkalis, acids, and water molecules.
 18. The memory device of claim 1,wherein the active layer comprises material that can dissociate in atleast one of an electrical field and under light radiation.
 19. Thememory device of claim 18, wherein the material that can dissociate onanions that are selected from the group consisting of I, Br, Cl, F,ClO₄, AlCl₄, PF₆, AsF₆, AsF₄, SO₃CF₃, BF₄, BCl₄, NO₃, POF₄, CN, SiF₃,SiF₆, SO₄, CH₃CO₂, C₆H₅CO₂, CH₃C₆H₄SO₃, CF₃SO₃, N(SO₃CF₃)₂,N(CF₃SO₂)(C₄F₉SO₂), N(C₄F₉SO₂)₂, alkylphosphate, organoborate,bis-(4-nitrophenil) sulfonilimide, and poly(styrenesulfonate)(polyanions).
 20. The memory device of claim 18, wherein thematerial that can dissociate on cations that are selected from the groupconsisting of Li, Na, K, Rb, Cs, Ag, Ca, Mg, Zn, Fe, Cu, H, and NH₄. 21.The memory device of claim 1, wherein the functional media comprisesporous dielectric material.
 22. The memory device of claim 21, whereinthe porous dielectric material is selected from the group consisting ofSi, amorphous Si, silicon dioxide (SiO₂), aluminum oxide (Al₂O₃), copperoxide (Cu₂O), titanium dioxide (TiO₂), boron nitride (BN), vanadiumoxide (V₂O₃), carbon tri-nitride (CN₃), ferroelectric materials andbarium-strontium titanate ((Ba, Sr) TiO₃).
 23. The memory device ofclaim 1, thicknesses of the first electrode and the second electrodebeing at least about 0.01 μm or at most about 10 μm.
 24. The device ofclaim 1, the active layer having a thickness of at least about 0.001 μmor at most about 5 μm.
 25. The device of claim 1, a thickness of theactive layer is about 10 to about 500 times greater than a thickness ofthe passive layer.
 26. A method of fabricating the memory device ofclaim 1, comprising: forming a first electrode on a substrate; forming apassive layer of the functional media on the first electrode; forming anactive layer of the functional media on the passive layer; and forming asecond electrode on the active layer.
 27. The method of claim 26 furthercomprising forming the active layer via a chemical vapor depositionprocess.
 28. The method of claim 26 further comprising forming theactive layer via a gas phase reaction process.
 29. The method of claim26, further comprising forming the active layer formed via a spincoating process or a liquid phase reaction process.
 30. The method ofclaim 26, further comprising applying a first voltage to the firstnon-copper electrode and the second electrode, to set an impedance stateof the organic memory device, the impedance state representinginformation content.
 31. The method of claim 26, further comprisingapplying a second voltage to the first electrode and the secondelectrode to determine an impedance state of the memory device, theimpedance state representing information content.
 32. A memory devicecomprising: a first electrode; a functional media formed over the firstelectrode, the functional media comprising a passive and active layerthat exchange electrons or holes to change an impedance state of thememory device and store information content, the impedance state changesbased on a migration of electrons or holes when subject to an externalelectric field or light radiation, the active layer having a thicknessthat is about 0.1 to about 500 times greater than a thickness of thepassive layer, the thickness of the active from about 0.001 μm to about5 μm and the thickness of the passive layer from about 2 Å to about 0.1μm; and a second electrode formed over the functional media.